/* Libart_LGPL - library of basic graphic primitives
* Copyright (C) 1998 Raph Levien
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include "config.h"
#include "art_rect_uta.h"
/* Functions to decompose a microtile array into a list of rectangles. */
/**
* art_rect_list_from_uta: Decompose uta into list of rectangles.
* @uta: The source uta.
* @max_width: The maximum width of the resulting rectangles.
* @max_height: The maximum height of the resulting rectangles.
* @p_nrects: Where to store the number of returned rectangles.
*
* Allocates a new list of rectangles, sets *@p_nrects to the number
* in the list. This list should be freed with art_free().
*
* Each rectangle bounded in size by (@max_width, @max_height).
* However, these bounds must be at least the size of one tile.
*
* This routine provides a precise implementation, i.e. the rectangles
* cover exactly the same area as the uta. It is thus appropriate in
* cases where the overhead per rectangle is small compared with the
* cost of filling in extra pixels.
*
* Return value: An array containing the resulting rectangles.
**/
ArtIRect *
art_rect_list_from_uta (ArtUta *uta, gint max_width, gint max_height,
gint *p_nrects)
{
ArtIRect *rects;
gint n_rects, n_rects_max;
gint x, y;
gint width, height;
gint ix;
gint left_ix;
ArtUtaBbox *utiles;
ArtUtaBbox bb;
gint x0, y0, x1, y1;
gint *glom;
gint glom_rect;
n_rects = 0;
n_rects_max = 1;
rects = art_new (ArtIRect, n_rects_max);
width = uta->width;
height = uta->height;
utiles = uta->utiles;
glom = art_new (int, width * height);
for (ix = 0; ix < width * height; ix++)
glom[ix] = -1;
ix = 0;
for (y = 0; y < height; y++)
for (x = 0; x < width; x++)
{
bb = utiles[ix];
if (bb)
{
x0 = ((uta->x0 + x) << ART_UTILE_SHIFT) + ART_UTA_BBOX_X0 (bb);
y0 = ((uta->y0 + y) << ART_UTILE_SHIFT) + ART_UTA_BBOX_Y0 (bb);
y1 = ((uta->y0 + y) << ART_UTILE_SHIFT) + ART_UTA_BBOX_Y1 (bb);
left_ix = ix;
/* now try to extend to the right */
while (x != width - 1 &&
ART_UTA_BBOX_X1 (bb) == ART_UTILE_SIZE &&
(((bb & 0xffffff) ^ utiles[ix + 1]) & 0xffff00ff) == 0 &&
(((uta->x0 + x + 1) << ART_UTILE_SHIFT) +
ART_UTA_BBOX_X1 (utiles[ix + 1]) -
x0) <= max_width)
{
bb = utiles[ix + 1];
ix++;
x++;
}
x1 = ((uta->x0 + x) << ART_UTILE_SHIFT) + ART_UTA_BBOX_X1 (bb);
/* if rectangle nonempty */
if ((x1 ^ x0) | (y1 ^ y0))
{
/* try to glom onto an existing rectangle */
glom_rect = glom[left_ix];
if (glom_rect != -1 &&
x0 == rects[glom_rect].x0 &&
x1 == rects[glom_rect].x1 &&
y0 == rects[glom_rect].y1 &&
y1 - rects[glom_rect].y0 <= max_height)
{
rects[glom_rect].y1 = y1;
}
else
{
if (n_rects == n_rects_max)
art_expand (rects, ArtIRect, n_rects_max);
rects[n_rects].x0 = x0;
rects[n_rects].y0 = y0;
rects[n_rects].x1 = x1;
rects[n_rects].y1 = y1;
glom_rect = n_rects;
n_rects++;
}
if (y != height - 1)
glom[left_ix + width] = glom_rect;
}
}
ix++;
}
art_free (glom);
*p_nrects = n_rects;
return rects;
}
